(a) Technical Field
The present invention relates to an alarm system equipped in a vehicle which can detect the negligence of a vehicle driver in observing the front view targets and release an alarm to alert the driver to avoid any possible danger.
(b) Background Art
There have been introduced many warning devices in a vehicle equipped with a camera to monitor driver's eye gaze directions and gives out an alarm against the driver in case he fails to observe the targets in his front field of view.
For example, Japanese Pat. No. 3232873 discloses a device which emits an invisible ray to the eyes of a driver and detects the direction of a driver's eye gaze based on the reflected light.
Japanese Pat. No. 4032994 discloses a method of detecting the direction a driver's eye gaze by respectively obtaining the center of the white portion and that of the black portion (pupil) of the driver's eyeball.
Japanese Patent Application Publication No. 2002-331850 discloses a device which detects target awareness of a driver by determining the driver's intention of vehicle operation behavior by analyzing his vehicle operation pattern based on the parameters calculated by using Hidden Marcov Model (HMM) for the frequency distribution of the driver's eye gaze wherein the eye gaze direction of the driver is detected as a means to determine the driver's vehicle operation direction.
Japanese Patent Application Publication No. H 11-304428 discloses a system to assist a vehicle driver for his operation by alarming a driver when he is not fully unattended to his driving in observing his front view field based on the fact that his eye blinking is not detected or an image which shows that the driver's eyeball faces the front is not detected for a certain period of time.
Japanese Patent Application Publication No. H 7-69139 discloses a device which determines the target awareness of a driver based on the distance between the two eyes of the driver calculated based on the images pictured from the side facing the driver.
As disclosed in the above-mentioned references, the conventional methods of detecting driver's target unawareness comprises: observing driver's driving behavior during vehicle operation by using a camera; and judging the driver's failure to observe front view targets in case the driver's eye gaze is failed to observe the front view target for a certain period of time thereby giving out a warning signal against the driver for negligence of front view target awareness.
However, it has not been easy to exactly judge the state of a driver with respect to the front view targets awareness by the conventional methods because the drivers' vehicle operation behaviors are very diverse and it is highly likely that many false alarms will be produced.
Further, the driver's failure to observe the front view targets for a certain period of time does not necessarily mean that the driver is placed in danger. Thus repeated release of alarms against the driver, which have not been necessary, may have been sometimes a nuisance and even make the driver immune to the alarm signal.
Therefore, the object of this invention is to provide an alarm system equipped in a vehicle which is designed to release alarm only when necessary by detecting the real danger of a driver during vehicle operation due to the driver's failure to observe the front view targets.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.